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It’s no secret that oil is king, especially in western North Dakota. According to the U.S. Geological Survey, the Bakken Formation is the largest continuous oil resource that it has ever characterized. It is estimated that the Bakken and Three Forks Formations combined hold between 300 and 900 billion barrels (Bbbl) of oil, with 10 to 24 Bbbl being technically recoverable using current technologies.

Steve Hawthorne, Energy & Environmental Research Center (EERC) Senior Research Manager, and the staff working in the EERC’s Environmental Chemistry Laboratory have been developing methods to find cheaper and better tools to extract the available oil in both conventional and unconventional reservoirs by using carbon dioxide (CO2), one of which was finding a new way to measure the minimum miscibility pressure (MMP), the optimum pressure at which to extract oil from formations.

Conventional wisdom states that in order to see oil flow activity, the MMP would need to be reached and maintained; however, Hawthorne’s lab tests show changes in activity both below and above the MMP.

To illustrate these findings, Hawthorne produced a video to show how CO2and crude oil interact at reservoir conditions. The video was recorded in a high-pressure cell in the lab and was shot at the speed of one frame per second, which was just enough resolution to see oil movement and provide visual support that confirms Hawthorne’s earlier hypothesis.

“The video is a visual demonstration that explains that the MMP for a particular system is not a line in the sand,” said Hawthorne.“A lot goes on before the MMP is reached, a lot goes on at higher pressures, and you lose a lot of hydrocarbon as you drop pressure, even though you are above the MMP. That is shocking to a lot of people,” he said.

Other experiments in the lab reveal that substantial amounts of oil can be extracted from the Lower, Middle, and Upper Bakken utilizing CO2, but that a greater understanding of the mechanisms controlling oil recovery will be needed to best apply the technology in the Bakken system. However, using CO2 to increase oil recoveries by a few percent in unconventional reservoirs such as the Bakken could be huge, since even a 1% increase could equate to as much as 9 Bbbl of oil. The EERC’s Oil and Gas Group is currently working on establishing a pilot-scale CO2enhanced oil recovery project to demonstrate this method in the Bakken play.

The EERC, in close cooperation with Continental Resources, Inc.; Marathon Oil Company; and several of the Williston Basin’s other premier operating companies, is engaged in a research program to simultaneously improve Bakken system oil recovery and reduce its environmental footprint. The results of the 3-year program will increase the well productivity and economic output of North Dakota’s oil and gas resources, decrease environmental impacts of wellsite operations, and reduce demand for infrastructure construction and maintenance.

“A lot of what my lab does requires thinking outside the box. I may not know much about petroleum fields, and the folks I work with likely don’t know much about chemistry. We tend to look at things differently from one another—that’s one reason I enjoy working in different fields,” said Hawthorne.

View the “Pressurized COand Crude Oil Interaction” video here.